Mapping texture to repeat itself from a bigger map
As everything will be packed onto just 1 texture, tiling would repeat the whole texture and this is unwanted. Nowadays engines don't have problems with polygons so if you want a part of that packed texture to repeat simply create the surface of many polygons each mapped to the same area on the packed image.

To utilize multiple tiling textures you would need support for multiple materials with multiple UV maps. Each section of model would then have different material with different UV map. Blender can do this but I have no clue about the format which you might use.